The Range of Motion Products v. Armaid Company Decision and the Evolving Scope of Ornamental vs. Functional Design
Design patents have long occupied a unique space in intellectual property law. Unlike utility patents, which protect how something works, design patents protect how something looks. That distinction sounds simple, but in practice it often becomes one of the most complex and heavily litigated issues in patent law.
A recent Federal Circuit decision in Range of Motion Products, LLC v. Armaid Company Inc., No. 2023-2427 (Fed. Cir. Feb, 2, 2026) provides important clarification on how prior art influences the scope of a design patent claim, particularly through the lens of the ornamental versus functional distinction. It has meaningful implications for product designers, consumer goods companies, and IP litigators alike.
As more fully explained below, that decision reinforces a principle that has existed in doctrine for years but has often been inconsistently applied: the more constrained a design is by function or prior art, the narrower its protectable scope becomes.
Design Patent Basics
Before diving into the case, it is important to understand the legal framework that governs design patents.
What Does a Design Patent Protect?
Under 35 U.S.C. § 171, a design patent protects:
The ornamental design of an article of manufacture
The visual appearance, not the functional aspects
The design as shown in the patent drawings
This means that protection is limited to what is depicted, and not what the product does.
The Ornamental vs. Functional Distinction
One of the most critical concepts in design patent law is the distinction between ornamental and functional features.
· Ornamental features are those chosen for aesthetic reasons
· Functional features are dictated by how the product works
· If a feature is purely functional, it is not protectable under design patent law
Courts have repeatedly emphasized that design patents cannot be used to monopolize functional aspects of products. Prior art is key in determining: 1) Whether a design is novel and non-obvious, and 2) How broadly or narrowly the patent claim should be construed. When prior art is crowded (i.e., many similar designs already exist) the scope of protection becomes narrower.
Background in Range of Motion
The dispute in Range of Motion arose within the increasingly competitive market for therapeutic and self-massage devices, a sector that has seen substantial growth due to rising consumer interest in recovery tools, physical therapy aids, and at-home wellness solutions. Both parties operated in this space, offering products designed to assist users in applying targeted pressure to muscles for relief and rehabilitation.
The Plaintiff, Range of Motion Products (“RoM”) owned a design patent directed to a specific configuration of a massage device. The patented design focused on the visual arrangement and overall appearance of the product, including its shape, structure, and the relationship between its components as depicted in the patent drawings. As is typical in design patent cases, the protection did not extend to how the device functioned mechanically, but rather to how it appeared to an ordinary observer.
Armaid Company (“Armaid”), a competitor in the same market, developed and sold a product that RoM alleged was substantially similar in appearance to its patented design. This led to claims of design patent infringement. But Armaid did not simply deny similarity. Instead, it mounted a broader defense that challenged both the scope and the validity of the asserted design patent, arguing that the claimed design was heavily constrained by functional considerations and closely aligned with prior art already available in the field.
This factual context is significant because designs in the therapeutic device market are often shaped in part by ergonomic and functional requirements. For example, devices intended to
apply pressure to muscles must accommodate the human body, provide leverage, and maintain stability during use. These constraints can naturally lead to similar structural features across competing products. As a result, distinguishing between what is truly ornamental versus what is functionally necessary becomes particularly difficult, and – as a result – legally significant.
Against this backdrop, the case evolved beyond a straightforward side-by-side comparison of two products (or between a product and a patented design as shown in patent drawings). Instead, it became a deeper inquiry into how courts should interpret design patents in industries where form is closely tied to function and where prior art already occupies much of the available design space.
This dispute forced the court to confront a foundational issue in design patent law: How should prior art and functional constraints shape the interpretation and enforceability of a design patent claim? This question has broad implications not only for the parties involved, but also for any business seeking to rely on design patents in crowded or function-driven industries.
Key Legal Questions Presented
The case ultimately revolved around several intertwined legal questions that sit at the heart of modern design patent jurisprudence:
1. To what extent does prior art limit the scope of a design patent? When similar designs already exist, courts must determine how much room remains for exclusive rights, and whether small differences are sufficient to sustain a claim of infringement.
2. How should courts distinguish between ornamental and functional features? This requires careful analysis of whether particular design elements were chosen for aesthetic reasons or dictated by practical necessity.
3. When does functional necessity narrow a design claim to near insignificance? In some cases, the combination of prior art and functional constraints may leave only a very narrow band of protectable design space, if any, thus raising questions about enforceability.
4. What role should the “ordinary observer” test play in a crowded field? Courts must consider how an ordinary purchaser would perceive similarities, but that perception is informed by the existing landscape of prior designs.
While these questions are not new, the court’s treatment of them in this case provided renewed clarity and a more structured framework for applying long-standing principles. The decision illustrates how doctrinal concepts, such as the ornamental/functional distinction and prior art limitations, operate together in practice.
A Structured Approach to Ornamentality, Functionality, and Scope
The court’s analysis in Range of Motion brought together several foundational principles of design patent law and applied them in a cohesive, practical way. Rather than treating prior art, functionality, and infringement as separate inquiries, the court approached them as interconnected factors that collectively define the true scope of the design patent at the center of the controversy. At a high level, the decision reinforces that design patent protection is highly context-dependent, and that context is shaped by both the existing design landscape and the functional realities of the product category.
1. Prior Art as a Primary Limiting Force
The court began by reaffirming the principle that prior art significantly constrains the scope of a design patent claim. In fields where many similar designs already exist, the “design space” available for exclusive rights becomes increasingly limited. As a result:
The range of permissible variation shrinks
Differences that might otherwise seem minor can become legally dispositive
The claimed design must be interpreted in direct relation to what came before it
This approach aligns with the principle that design patents do not exist in a vacuum. Instead, they must be evaluated in the context of the visual landscape already available to consumers. In practical terms, this means that in a crowded field (e.g., therapeutic devices) protection may extend only to a very specific and narrowly defined visual configuration, rather than a broad concept or general shape.
2. Functional Constraints and the Limits of Ornamentation
Building on its prior art analysis, the court placed significant emphasis on the ornamental versus functional distinction, a cornerstone of design patent law. The court explained that features dictated by function are given little to no weight in the infringement analysis. This principle operates as a filter: before comparing designs, courts must discount or give less weight to elements that are functionally required. For example:
If a product must adopt a certain shape to perform its intended purpose
And that shape is already reflected in prior art
Then that feature carries little, if any, weight in defining the design patent’s protectable scope
This reasoning is consistent with Federal Circuit precedent, including:
Egyptian Goddess, Inc. v. Swisa, Inc., 543 F. 3d 665 (Fed. Cir. 2008), which established the modern “ordinary observer” test informed by prior art
Richardson v. Stanley Works, Inc., 597 F.3d 1288 (Fed. Cir. 2010), which emphasized discounting functional elements when assessing design patent scope
By integrating these precedents, the court underscored that ornamentality is not evaluated in isolation, but in conjunction with both function and the prior art.
3. The Emergence of a “Narrow Band” of Protection
Perhaps the most significant conceptual takeaway from the aforementioned decision is the articulation of a “narrow band” of protection. The court explained that when two conditions are
present: 1) A dense field of prior art, and 2) A strong functional constraint on design, the resulting scope of protection may be extremely limited. In such cases, the design patent may effectively cover only designs that are nearly identical to the claimed embodiment.
4. A Unified Framework for Design Patent Interpretation
What distinguishes this Federal Circuit decision is not any single doctrinal innovation, but rather the way the court synthesized multiple principles into a unified analytical framework. The ruling makes clear that:
Prior art informs the baseline for comparison
Functional features are filtered out or minimized
The remaining ornamental elements define the true scope of the claim
In crowded, function-driven fields, this process often yields a narrow scope of protection
This structured approach provides clearer guidance for both courts and litigants, reducing ambiguity in how design patent claims should be construed for purposes of determining infringement.
5. Impact and Future Implications
This ruling will guide future courts facing similar issues. While it does not radically alter existing law, it meaningfully clarifies how established doctrines should be applied in practice, particularly in industries in which design and function are closely intertwined. Several key implications are likely to emerge:
Greater emphasis on contextual comparison Courts will more rigorously analyze design patents against the full scope of relevant prior art, rather than focusing solely on side-by-side product comparisons.
Increased scrutiny of functional elements Litigants should expect deeper examination of whether specific features are truly ornamental or dictated by use.
More predictable (but narrower) claim interpretation The structured framework may improve consistency in outcomes, but it also signals that many design patents will be interpreted more narrowly than some patentees might expect.
Strategic shifts in litigation and prosecution Plaintiffs may need stronger evidence of distinct ornamentation, while defendants will continue to leverage prior art and functionality to limit claim scope.
Although the case has not yet become a widely cited cornerstone of design patent law in this country, its clear and pragmatic analysis positions it to become an influential reference point in the future. For practitioners, it serves as a reminder that the strength of a design patent lies not just in its existence, but in the distinctiveness of what it actually claims in light of the real-world design landscape.
How Range of Motion Impacts Design Protection Moving Forward
The Range of Motion decision carries meaningful implications for businesses and designers operating in industries in which product form is closely tied to function. Perhaps the most immediate takeaway is that companies can no longer assume that obtaining a design patent will result in broad or easily enforceable protection. Instead, the decision underscores that the strength of a design patent depends heavily on how visually distinct the design is when viewed against existing products and functional constraints. In crowded markets (e.g., fitness equipment, medical devices) this means that even well-drafted design patents may ultimately provide only narrow protection if the underlying design space is already saturated.
For designers, the ruling highlights the importance of intentional, documentable aesthetic
choices. When design decisions are driven primarily by engineering or ergonomic requirements, the resulting product may struggle to qualify for meaningful design patent protection. This places greater value on collaboration between design teams and legal counsel early in the development process. By identifying which aspects of a product can be modified for visual distinctiveness, without compromising functionality, companies can better position themselves to secure enforceable rights. In practice, this may lead to more iterative design processes, where aesthetics are not treated as an afterthought, but as a strategic component of intellectual property protection.
From a business perspective, the case also signals a shift in how companies should evaluate risk and competition. Competitors may be able to design around existing patents more easily than expected, particularly where functional requirements limit available design options. As a result, companies should consider building layered IP strategies that combine design patents with other forms of protection, such as utility patents, trademarks, or trade dress where applicable. At the same time, businesses must be more cautious when asserting design patents in litigation, as courts are increasingly willing to narrow claim scope based on prior art and functionality. This creates a more nuanced enforcement environment, where success depends not just on similarity, but on a carefully framed understanding of what is truly protectable.
The Range of Motion decision reinforces a fundamental reality of design patent law: protection is inherently limited by both what came before and what must exist for a product to function. While design patents remain a valuable tool for safeguarding product appearance, their scope is neither automatic nor expansive. Instead, their scope is shaped by a careful balancing of ornamentation, functionality, and the relevant prior art.
For businesses and designers, the message is clear. Success in leveraging design patents will depend on creating products that are not only functional, but visually distinctive in ways that can withstand close legal scrutiny. As courts continue to refine the boundaries of design patent protection, those who approach design with both creativity and legal foresight will be best positioned to secure meaningful and enforceable rights.
If you’re interested in learning more about this topic or how the principles discussed in this article may impact your business, don’t hesitate to contact us at info@patentxl.com or at +1(610)871-2024.
